If a nearsighted person has a far point df that is 3.50m from the eye, what is the focal length f1 of the contact lenses that the person would need to see an object at infinity clearly? Express your answer in meters. If a farsighted person has a near point that is 0.600m from the eye, what is the focal length f2 of the contact lenses that the person would need to be able to read a book held at 0.350m from the person's eyes? Express your answer in meters.